How to declare Pointer variables in Type Library?

Ma Xiaoguang

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May 13, 2008, 10:24:55 PM5/13/08

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Dear ladies and gentlemen,

I need to declare Pointer variables in Type Library for an ActiveX
component. But I don't know which data type is corresponding to Pointer in
Type Library. Please give me some suggestions. Thank you very much.

Best regards.

Xiaoming

Remy Lebeau (TeamB)

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May 14, 2008, 12:55:49 PM5/14/08

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"Ma Xiaoguang" <maxiaogu...@hotmail.com> wrote in message
news:482a...@newsgroups.borland.com...

> I need to declare Pointer variables in Type Library for
> an ActiveX component.

Why? Untyped pointers are safe in ActiveX. What are you trying to
accomplish exactly?

> But I don't know which data type is corresponding to
> Pointer in Type Library.

void*

Gambit

Ma Xiaoguang

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May 14, 2008, 8:44:23 PM5/14/08

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Hi Remy,

> Why? Untyped pointers are safe in ActiveX. What are you trying to
> accomplish exactly?

One of my friend asked me to encapsulate component MCDBurner in ActiveX.
In this component, it has the following method:

function InsertMemoryFile(DestinationPath, LongFileName, ShortFileName:
String; Attr: Byte; Memory: Pointer; Size: Cardinal): Integer;

So, I need to declare this method in Type Library, and with which to call
the original method.

That's why I need to declare Pointer variable (actually Pointer
parameter) in Type Library.

May thanks for your help.

Best regards.

Xiaoming

Ma Xiaoguang

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May 15, 2008, 1:53:22 AM5/15/08

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Hi Remy,

> void*

I can not specify void* as the data type in Type Library. Give me some
suggestions, please. Thank you very much.

Best regards.

Xiaoming

Remy Lebeau (TeamB)

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May 15, 2008, 1:03:12 PM5/15/08

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"Remy Lebeau (TeamB)" <no....@no.spam.com> wrote in message
news:482b19b5$1...@newsgroups.borland.com...

> Untyped pointers are safe in ActiveX.

I meant *unsafe*.

Gambit

Remy Lebeau (TeamB)

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May 15, 2008, 1:15:30 PM5/15/08

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"Ma Xiaoguang" <maxiaogu...@hotmail.com> wrote in message

news:482b8765$1...@newsgroups.borland.com...

> One of my friend asked me to encapsulate component
> MCDBurner in ActiveX. In this component, it has the following
> method:
>
> function InsertMemoryFile(DestinationPath, LongFileName, ShortFileName:
> String; Attr: Byte; Memory: Pointer; Size: Cardinal): Integer;
>
> So, I need to declare this method in Type Library, and with
> which to call the original method.

I suggest you implement your ActiveX object to accept an IStream as input
instead of trying to use a raw memory pointer (which you can't do in ActiveX
anyway). The VCL has a TStreamAdapter class available that exposes IStream
access to a TStream. Your friend can load his data into any TStream he
wants, such as a TMemoryStream or TFileStream, then use TStreamAdapter to
pass an IStream to your ActiveX, which can extract the raw bytes and pass
them to MCDBurner as needed, ie (untested):

public
function InsertData(DestinationPath, LongFileName, ShortFileName:
WideString; Attr: Byte; Data: IStream): Integer; safecall;

function TMyActiveXObject.InsertData(DestinationPath, LongFileName,
ShortFileName: WideString; Attr: Byte; Data: IStream): Integer; safecall;
var
statstg: TStatStg;
Buf: PByte;
NumRead: ULONG
begin
Data.Stat(statstg, STATFLAG_NONAME);
GetMem(Buf, statstg.cbSize.LowPart);
try
Data.Read(Buf, statstg.cbSize.LowPart, NumRead);
Result := Burner.InsertMemoryFile(DestinationPath, LongFileName,
ShortFileName, Attr, Buf, NumRead);
finally
FreeMem(Buf);
end;
end;

Gambit

Ma Xiaoguang

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May 15, 2008, 9:07:13 PM5/15/08

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Hi Remy,

Many thanks for your detailed and patient explanations.

Best regards.

Xiaoming